package com.zlc.common.util.tree;

import java.util.*;

public class TreeUtil {

    public static <T extends Node<T>> List<T> buildTree(List<T> nodes) {
        Map<String, T> nodeMap = new HashMap<>();
        List<T> roots = new ArrayList<>();

        for (T node : nodes) {
            nodeMap.put(node.getCode(), node);
        }

        for (T node : nodes) {
            String parentCode = node.getParentCode();
            if (parentCode == null || parentCode.isEmpty()) {
                roots.add(node);
            } else {
                Node<T> parentNode = nodeMap.get(parentCode);
                if (parentNode != null) {
                    if (parentNode.getChildren() == null) {
                        parentNode.setChildren(new ArrayList<>());
                    }
                    parentNode.getChildren().add(node);
                    parentNode.getChildren().sort(Comparator.comparing(t -> t.getSortNum() != null ? t.getSortNum() : 0));
                } else {
                    roots.add(node);
                }
            }
        }

        roots.sort(Comparator.comparing(t -> t.getSortNum() != null ? t.getSortNum() : 0));
        return roots;
    }
}
